FRP (Fiber-Reinforced Plastic) composed of a composite of fiber and plastic exhibits a high strength, and a cable (rope or rod) fabricated using FRP is light in weight in comparison with PC stranded wire and has excellent characteristics such as a high corrosion resistance and a non-magnetic property. Fibers such as carbon fibers, glass fibers and Kevlar fibers have been used as fiber material employed in FRP, and resins such as epoxy resin, polyamide resin and phenol resin have been used as the plastic material in FRP. FRP cables are being used as the stressing members in prestressed concrete, by way of example.
While an FRP cable exhibits a high strength equivalent to that of PC stranded wire with regard to tension in the longitudinal direction, it is weak against local shearing force and surface scratching, etc. As a consequence, when a socket is secured to the end portion of the cable by directly forcing in a wedge in a manner similar to that of a PC stranded wire, severance due to shearing damage and sliding due to surface-layer damage occur and a high anchoring efficiency between the cable and socket cannot be obtained.
In order to arrange it so that shearing force will not concentrate in the cable locally at the socket anchoring portion (fixing portion), the conventional approach is to insert the end of the cable into the socket, followed by filling the gap between the cable and the socket with a thermosetting resin and then hardening the resin, or filling the gap with an expanding agent and integrating the cable and the socket owing to the pressure of expansion of the expanding agent (e.g., see Japanese Patent Application Laid-Open No. 1-272889).
With regard to both thermosetting resin and expanding agent, however, it takes a certain amount of time for the resin to harden or for the expanding agent to expand. Further, since stringent temperature management is necessary during hardening or expansion, a special apparatus and space for the apparatus are required. If is difficult to secure the socket to the cable end at the work site, etc., and securing is necessary beforehand at the factory.